Polyhedral oligomeric silsesquioxane (POSS) means a siloxane-based material having a three dimensional structure, and is generally represented by a molecular formula of (RSiO1.5)n.
POSS has a silicon-oxygen bond which is an inorganic framework constituting a basic structure of a molecule, and R may consist of various organic groups. Therefore, POSS has been studied as an organic-inorganic hybrid nano-scale material.
Since POSS has a molecular diameter in the range of several nanometers, it exhibits a quantum size effect, a quantum surface effect, a quantum interface effect, etc., and due to these quantum properties, the POSS material may have specific physical and chemical properties in many different aspects such as thermal conductivity, electrical conductivity, optical and magnetic behaviors, hydrophilicity, lipophilicity, etc., and also allows introduction of these properties onto the surface of a polymer, etc.
Particularly, POSS has a basic structure consisting of silicon-oxygen bonds (silsesquioxane type), and therefore, the molecular structure has very high physical and chemical stability and high thermal resistance and flame resistance. Under high temperature and high pressure conditions, the inorganic framework of POSS is broken to produce silica (SiO2), which may form a separate coating layer. This coating layer may very effectively function as a protecting layer.
Further, a variety of functional groups may bind to silicon atoms in the basic silsesquioxane structure of POSS, and therefore, it is easy to provide many different new physical properties depending on structures of organic groups to be introduced.